Geoscience Reference
In-Depth Information
facture in a laboratory of the chemical of interest generally eliminates the need for repeated
collection (ATCM,
2009
). Environmental impact remains a concern if the target organism
is rare, has a restricted distribution, and/or the collection is focused on a particular popu-
lation (Hunt and Vincent,
2006
), or if the organism is already suffering from other envir-
onmental pressures, such as climate change. Also, anthropogenic pressures (such as heli-
copter landings, lights from submersibles, effects of camping or skidoos, etc.) can have an
The extraction of polymetallic sulfide deposits will be relying on new technologies
and methods; their impact is as yet unknown. It is expected that the drifting particles pro-
duced by deep-sea sulfide mining have the potential to smother, clog, and contaminate
nearby vent communities. Organisms surviving these perturbations would be subject to a
radical change in habitat conditions with hard substrata being replaced by soft particles set-
tling from the mining plume. Mining could also potentially alter hydrologic patterns that
supply vent communities with essential nutrients and hot water. A further problem may
arise during dewatering of ores on mining platforms, resulting in discharge of highly nu-
trient enriched deep water into oligotrophic surface waters, which can drift to nearby shelf
areas. Because most invertebrate diversity at vents is found in rare species, habitat destruc-
tion by mining can be potentially devastating to local and regional populations (Secretariat
of the Convention on Biological Diversity,
2008
). Other potential sites for mining include
manganese nodule fields on abyssal plains and cobalt-rich crusts on the sides of seamounts.
The environmental impacts of such mining are unknown, but would involve disturbance to
Effects of offshore exploitation of oil and gas on seep ecosystem function and biod-
iversity are not well documented. Exploratory drilling and the installation and operation
of production platforms will produce localized and widely spaced disturbances. Depletion
of subsurface oil and gas reservoirs may eventually affect the energy supply to seep com-
munities, but this remains to be investigated. A more widespread impact may come from
the exploitation of subsurface gas hydrate deposits. These reserves of methane ice occupy
significant volumes within the seabed of continental margins worldwide. Recent global es-
